test: simplify typed conversions

ui/src/ui/controllers/usage.node.test.ts

@@ -207,7 +207,7 @@ function createStorageMock() {
       return store.get(key) ?? null;
     },
     setItem(key: string, value: string) {
-      store.set(key, String(value));
+      store.set(key, value);
     },
     removeItem(key: string) {
       store.delete(key);